This invention relates to an orthodontic appliance to treat malocclusion, and particularly to the improvement of an arch wire holder attached to a user's teeth in order to hold an orthodontic arch wire thereat.
FIG. 1 illustrates the newest advanced technique for the treatment of malocclusion. As illustrated, brackets (1) constituting the arch wire holders are fixed to teeth (2.sub.11), (2.sub.12), . . . (2.sub.17), and one or more orthodontic wires (3) are inserted into these brackets (1) and are fixed therein. The malocclusion is corrected forces applied to the subject teeth by elasticity of the arch wire (3). For example, as shown in FIG. 2, when the central incisors (2.sub.11) are protruding outward, as shown by solid lines, and are to be corrected to have normal occlusion, as shown by broken lines, bands (4) are attached to teeth (2.sub.11) and brackets (1) are bonded to these bands (4) as illustrated in FIG. 1. Then one curved orthodontic arch wire (3) is fixed to these brackets (1), and its elasticity is used to apply corrective forces to the teeth for the treatment.
The major disadvantage of this method is that, since the brackets (1) are attached to the outside (buccal side) surface of the teeth (2.sub.11), brackets (1) are exposed when the patient opens his mouth, affecting his facial appearance. To solve this problem, the present applicant has already proposed an appliance, disclosed in U.S. Pat. Nos. 4,209,906 and 4,354,833), in which all brackets (1) are fixed inside (lingual side) surface the teeth (2.sub.11), (2.sub.12), . . . (2.sub.17) as shown in FIG. 3, and arch wire (3) is put in the slots of these brackets. This makes the brackets (1) and arch wire (3) invisible even when the user's mouth is opened, and greatly reduces the mental burden of the patient.
Both in the conventional method (FIG. 1) and new method (FIG. 3), the envelope linking the teeth is almost elliptical.
However, in the conventional brackets (1) shown in FIG. 1, the arch wire fixing slot (5) was straight, making it difficult to insert therein an arch wire (3) which was curved in advance. The wire here has to be curved and adjusted for each bracket. This requires a considerable amount of the dentist's time and causes the originally carefully bent arch wire to be deformed.